Daylight developing tank for roll films having protective paper strips



Nov. 2, 1954 M. LE DAYLIGHT DEVELOPING HAVING PROTECTIVE PAPER il 5, 195

iled Apr SJAK TANK FOR ROL STRI l ILMS HIS ATTORN EYS United StatesPatent 0 DAYLKGHT DEVELOPING TANK FOR ROLL FILMS HAVDIG PROTECTIVE PAPERSTRIPS Michael Lesjalr, Ichenhausen, Germany Application April 5, 1951,Serial No. 219,365

Citrims priority, application Germany May 11, 1950 7 Claims. (Cl.95-0.5)

My present invention relates to a daylight developing tank for rollfilms having protective paper strips. More particularly, it relates tosuch a tank wherein, after separation of the protective paper strip, theroll film is drawn into spiral grooves on the flanges of a developingspool by means of a clamp atfixed to a pull-in band.

Daylight developing tanks of the above mentioned type have long beenknown and are described, for example, in the U. S. Patent No. 2,082,962.When treating roll films having protective paper strips in suchapparatus, the film could not be pulled into the developing containerdirectly from the film spool compartment, since the protective paperstrip first had to be removed. It was necessary to provide a second filmcompartment located parallel to the axis of the film spool compartment,into which the roll film was unwound upon pulling out of the protectivepaper strip. Before the film could be drawn out of the second filmcompartment by means of the pull-in band, it was necessary to seal thatcompartment against the entrance of light, while leaving the end of thefilm exposed, by some suitable means, then to open the cover of thedeveloping tank, afiix the clamp on the pull-in band to the protrudingend of the film, close the cover of the developing tank and finally,open the light sealing means for the second film compartment.

The main object of my invention is to simplify such apparatus and toeliminate the tedious procedure described above. In accordance with myinvention the clamp on the pull-in band is so arranged that the end ofthe film automatically enters the jaws of the clamp and is graspedthereby, when pulling out the protective paper strip. The introductionand treatment of the film in the developing tank may be carried out infull daylight. For this purpose the clamp is amxed at the film spoolcompartment in such a manner as to be releasable from outside the tank.This releasable attachment preferably is obtained by means of a bowedmetal rod that is arranged parallel to the axis of the film spoolcompartment and whose bowed-out portion, when swung in one direction,presses the clamp against the film spool compartment and holds it there,and when swung in the other direction, releases it. A projection on theclamp serves as the bearing surface for the bowed-out portion of themetal rod. This projection is located on the outside of the lower jaw ofthe clamp. In order to hold the clamp in position at the opening of thefilm spool compartment, the handle used to swing the bowed metal rod maybe locked. To insure a certain entrance of the beginning of the filmbetween the jaws of the clamp, the lower jaw of the clamp, that restsupon the top edge of the partition between the film spool compartmentand the developing container, is provided with a stripoif plate whichbears resiliently against the circumference of the roll film spool.

Means are provided in my improved apparatus whereby the clamp on thepull-in band may be closed from the outside. Such means may, forexample, consist of a resilient peg passing through the cover of thetank, whose lower end, when depressed against the action of a spring,touches the upper jaw of the clamp and upon further depression closesthe clamp. Instead of such a resilient peg one may also employ a bowedrod whose bowed portion upon being swung by means of an outside handlebears against the upper clamp jaw and pushes it down to close the clamp.

In order to guide the protective paper strip as it is 2,693,138 PatentedNov. 2, 1954 pulled ofi from the roll film spool, I provide a hingedguide plate above the film spool compartment, that forms a slit with thecover of the tank, through which the protective paper strip iswithdrawn. This hinged guide plate also serves to prevent loosening ofthe windings of the roll film, because when closed it rests upon theoutermost film winding under the influence of a spring. By thus insuringthat the film remains tightly wound in the film spool compartment, thefilm spool is protected against entrance of light. This protection issufficient to enable one, if desired, to clamp the beginning of the filmwith the cover of the tank removed in subdued light. Finally, tworesilient supporting metal strips that partially enclose the spool areprovided in the film spool compartment for holding the film spool. Theseassist the action of the strip-off plate at the lower jaw of the clamp.

An embodiment of my invention is illustrated by way of example in theaccompanying drawings wherein:

Fig. 1 is a cross section through a film spool compartment of the closeddeveloping tank, showing a film spool in the compartment and the clampfor attachment of the beginning of the film held against the top edge ofthe partition between the film spool compartment and the developingcontainer.

Fig. 2 is a plan view of the portion of the developing tank shown inFig. 1, with the tank cover and film spool removed, and the guide platefolded back.

Fig. 3 is a side view of the clamp with its jaws open.

Fig. 4 is a side view of the clamp and section of a bowed metal rod usedfor closing the clamp.

The portion of the daylight developing tank illustrated in Fig. 1 showsa film spool compartment 2 arranged above and alongside of thedeveloping container 1, which is closed by means of a cover 3. Afterinserting a roll film spool 4 provided with a protective paper strip 6into the film spool compartment 2, the guide plate 5 is f d d wn and theb innint of the paper strip 6 is pulled thereover into the positionshown. Since the guide plate 5, after being folded down, rests upon theouter winding of the film under the effect of a spring (n t sh wn). t fus th urther purpose of preventing a loosening of the film windings.

Before the cover 3 of the developing tank is closed, the clamp 8 thatserves to pull the film 7 into the developing container 1 is attached tothe top edge of the partition 2a, separating the film spool compartment2 from the developing container 1. This clamp (see Fig. 3) consists of alower fixed jaw 8 and an upper movable jaw 8a. The lower jaw 8 isprovided with a projection 8b that forms an acute angle therewith on theside away from the film spool compartment 2.

The attachment of the clamp at the upper edge of the partition 2a isaccomplished by means of a bowed metal rod 11 that is rotatably mountedthrough the side walls 9 and 10 of the developing tank parallel to theaxis of the film spool compartment 2. The bowed-out portion 11:: of therod fits into the acute angle formed between the fixed jaw 8 and theprojection 85 of the clamp upon turning the rod 11 from outside the tankby means of the handle 11b. and forces the projection 8b against thepartition 2a. In order to hold the clamp in its resultant position bymeans of the bowed rod 11, its handle 11b is logked by means of asuitable catch 9a on the tank wal The further procedure for developingthe film may take place in full daylight with the developing tankclosed. Upon pulling out of the protective paper strip 6, the beginning7a of the film comes into position between the jaws of the clamp 8 asshown in Fig. 1. To assist in threading the film beginning 7a into theclamp, a strio-ofi plate 8c is attached to the inner end of the fixedjaw 8. This strip-off plate consists of a thin arched strip of metalthat reaches beyond the free ends of the clamp jaws 8 and 8a, and which.when the clamp is attached to the partition 2a, resiliently lies againstthe outer-most film winding on the film spool 4. By this means thebeginning 7a of the film 7 is stripped oil from the roll film spool 4,as the protective paper strip 6 is withdrawn, and necessarily comesbetween the open clamp jaws 8 and 8a. This condition may be recognizedby a resistance against further pulling out of the paper strip 6. Theaction of the strip-oft plate 80 is supported by that of the resilientsupporting metal strips 12 and 13 that partly surround the roll filmspool 4.

A peg 14 provided on the tank cover 3, whose normal position under theinfluence of a spring 15 is shown in Fig. 1, serves for closing theclamp. The peg 14 is so located that it passes through the cover 3directly above the movable clamp jaw 3a. As one depresses the peg 14 itsend 14a comes ,into contact with the movable clamp jaw 8a and uponfurther depression closes the clamp.

Instead of the peg 14, a bowed metal rod 16 (see Fig. 4) may be mountedin the side walls of the tank cover 3 parallel to the axis of the filmspool compartment 2, and serve to close the clamp jaws. Its bowedoutportion 16a, upon being swung from outside of the tank by means of asuitable handle, comes into contact with the movable clamp jaw 8a andupon further swinging in the direction of the arrow presses it down toclose the clamp. There also exists the possibility of replacing thebowed-out portion of the rod 16 by some other suitable projection. Sincethe guide plate 5, after being folded down, prevents any loosening ofthe film windings, it protects against the entrance of light thereto.Consequently, there results the possibility of carrying out the clampingof the film beginning 7a between the film javgs 8 and 8a with the cover3 removed in subdued daylig t.

As many apparently widely different embodiments of this invention may bemade without departing from the spirit and scope hereof, it is to beunderstood that this invention is not limited to the specificembodiments hereof except as defined in the appended claims.

I claim:

1. A daylight developing tank for roll films having protective paperstrips, which comprises a film spool compartment, a developingcontainer, a cover for both, a developing spool in the latter providedwith spirally grooved flanges, a pull-in band attached to the axle ofthe developing spool provided with a clamp having open jaws for graspingthe beginning of the film, means operable from outside the tank whenclosed for releasably holding said clamp against a fixed part of thetank interior with jaws extended in the path of the film from the filmspool compartment to the developing container, so that upon withdrawingthe film from the film spool the beginning of the film is automaticallyintroduced between the clamp jaws, and means also operable from outsidethe closed tank for pressing against the so held clamp to close its jawson the beginning of the film.

2. A daylight developing tank as claimed in claim 1, wherein the openclamp is releasably held against the top edge of a partition between thefilm spool compartment and the developing container by rotatable meanspassing through a wall of the developing tank and including an interiorextension that may be swung against the clamp.

3. A daylight developing tank as claimed in claim 1, wherein the meansfor releasably holding the open clamp in the path of the film includes abowed rod rotatably mounted in the side walls of the tank parallel tothe axis ofthe spool compartment.

4. A daylight developing tank as claimed in claim 1, wherein the lowerjaw of the clamp is provided with a strip-off plate whose edge bearsagainst the outer winding of the roll film in the film spoolcompartment.

5. A daylight developing tank as claimed in claim .1, wherein the coverfor the tank is provided with a peg passing therethrough, which uponbeing depressed bears against and closes the clamp.

6. A daylight developing tank as claimed in claim 1, wherein the coveris provided with a rod that is rotatably mounted in depending side wallsof the cover parallel to the axis of the film spool compartment andwhich has an extension that will swing upon rotation of the rod againstthe clamp to close it.

7. A dayli ht developing tank as claimed in claim 1, including a hingedguide plate above the film spool compartment which, when folded down,rests upon the roll film in said compartment and serves to guide theprotective paper strip to the outside of the tank.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 938,287 Taylor Oct. 26, 1909 2,484,378 Freeman Oct. '11, 1949

